Process for the preparation of acetamide derivatives

Abstract

The invention provides a process for the preparation of diphenylmethylthioacetamide (I) as described in Scheme 4 comprising reacting of the isothiouronium salt or its corresponding base of the formula IV with an acetamide of the formula XCH 2 CONH 2 , wherein X represents a halogen, M represents an alkali metal and A represents an anion, in a protic medium at a temperature of less than 100° C.

What is claimed is:  
     
       1. A process for the preparation of diphenylmethylthioacetamide (I) as described in Scheme 4 comprising reacting of the isothiouronium salt or its corresponding base of the formula IV with an acetamide of the formula XCH 2 CONH 2 , wherein X represents a halogen, M represents an alkali metal and A represents an anion, in a protic medium at a temperature of less than 100° C.:                    
     
     
       2. A process according to  claim 1 , wherein X is selected from the group consisting of chlorine and bromine atoms. 
     
     
       3. A process according to  claim 1  wherein the reaction takes place at a temperature between 60-70° C. 
     
     
       4. A process according to  claim 1  where M is a sodium atom. 
     
     
       5. A process for the preparation of Modafinil (III):                    
       comprising the steps of: 
       (a) preparing diphenylmethylthioacetamide (I) as described in Scheme 4 comprising reacting of the isothiouronium salt or its corresponding base of the formula IV with an acetamide of the formula XCH 2 CONH 2 , wherein X represents a halogen, M represents an alkali metal and A represents an anion, in a protic medium at a temperature of less than 100° C.:                    
       and 
       (b) reacting the diphenylmethylthioacetamide (I) with hydrogen peroxide to form Modafinil (III).